II.A. Evidence for Human Carcinogenicity
__II.A.1. Weight-of-Evidence Characterization
Classification -- A; human carcinogen

Basis -- based on sufficient evidence from human data. An increased lung cancer mortality was observed in multiple
human populations exposed primarily through
inhalation. Also, increased mortality from multiple internal organ cancers
(liver, kidney, lung, and bladder) and an increased incidence of skin cancer were observed in populations consuming
drinking water high in inorganic arsenic.

II.A.2. Human Carcinogenicity Data
Sufficient. Studies of smelter worker populations (Tacoma, WA; Magma, UT; Anaconda, MT; Ronnskar, Sweden;
Saganoseki-Machii, Japan) have all found an association between occupational arsenic exposure and lung cancer
mortality (Enterline and Marsh, 1982; Lee-Feldstein, 1983; Axelson et al., 1978; Tokudome and Kuratsune, 1976;
Rencher et al., 1977). Both proportionate mortality and cohort studies of pesticide manufacturing workers have shown
an excess of lung cancer deaths among exposed persons (Ott et al., 1974; Mabuchi et al., 1979). One study of a
population residing near a pesticide manufacturing plant revealed that these residents were also at an excess risk of
lung cancer (Matanoski et al., 1981). Case reports of arsenical pesticide applicators have also corroborated an
association between arsenic exposure and lung cancer (Roth, 1958).

CAS Number   Substance Name               Profiles   First Aid Guides   TPQ (Pounds)   EHS_RQ (Pounds)   
7784-34-1   ARSENOUS TRICHLORIDE      Prof         FA                      500                         5000   
98-05-5   BENZENEARSONIC ACID             Prof         FA                     10/10,000                1   
1327-53-3   ARSENOUS OXIDE                   Prof         FA                     100/10,000              5000   
1303-28-2   ARSENIC PENTOXIDE              Prof         FA                     100/10,000              5000   
58-36-6   PHENOXARSINE, 10,10'-OXYDI-  Prof          FA                     500/10,000              1   
7784-46-5   SODIUM ARSENITE                  Prof         FA                      500/10,000              1000   
7778-44-1   CALCIUM ARSENATE               Prof         FA                      500/10,000              1000   
10124-50-2   POTASSIUM ARSENITE          Prof         FA                      500/10,000              1,000   
7631-89-2   SODIUM ARSENATE                Prof          FA                     1,000/10,000            1000   1

1.6 How can arsenic affect children?    

This section discusses potential health effects from exposures during the period from conception to maturity at 18 years
of age in humans.

Children are exposed to arsenic in many of the same ways that adults are. Since arsenic is found in the soil, water, food,
and air, children may take in arsenic in the air they breathe, the water they drink, and the food they eat. Since children
tend to eat or drink less of a variety of foods and beverages than do adults, ingestion of contaminated food or juice or
infant formula made with arsenic-contaminated water may represent a significant source of exposure. In addition, since
children often play in the dirt and put their hands in their mouths and sometimes intentionally eat dirt, ingestion of
contaminated soil may be a more important source of arsenic exposure for children than for adults. In areas of the
United States where natural levels of arsenic in the soil and water are high, or in areas in and around contaminated
waste sites, exposure of children to arsenic through ingestion of soil and water may be significant. In addition, contact
with adults who are wearing clothes contaminated with arsenic (e.g., with dust from copper- or lead-smelting factories,
from wood-treating or pesticide application, or from arsenic-treated wood) could be a source of exposure. Because of
the tendency of children to taste things that they find, accidental poisoning from ingestion of pesticides is also a
possibility. Thus, although most of the exposure pathways for children are the same as those for adults, children may be
at a higher risk of exposure because of their lack of consistent hygiene practices and their curiosity about unknown
powders and liquids.

Children who are exposed to arsenic may have many of the same effects as adults, including irritation of the stomach
and intestines, blood vessel damage, skin changes, and reduced nerve function. Thus, all health effects observed in
adults are of potential concern in children. We do not know if absorption of arsenic from the gut in children differs from
adults. There is some information suggesting that children may be less efficient at converting inorganic arsenic to the
less harmful organic forms. For this reason, children may be more susceptible to health effects from inorganic arsenic
than adults.At present, there is no convincing evidence that inhaled or ingested arsenic can injure pregnant women or
their fetuses, although studies in animals show that large doses of arsenic that cause illness in pregnant females can
also cause low birth weight, fetal malformations, and even fetal death. Arsenic can cross the placenta and has been
found in fetal tissues. Arsenic is found at low levels in breast milk